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Heater Problem in my plow truck, help please!

Discussion in 'Truck & Equipment Repair' started by platinumpimps, Nov 8, 2008.

  1. platinumpimps

    platinumpimps Member
    Messages: 43

    I have a 92' Ford F250 with the 7.3 diesel. I have no heat! Stopped working recently. it does'nt blow very much at all when i turn to high. and it blows Cold most of the time. then maybe after a while of driving it will blow warm air but still wont blow much at all when on high. it just started to snow yesterday here in wi, and i just got my truck back from getting my plow working, and tranny rebuilt. so i would need to do this one myself. can anyone help me out here. any help is greatly appreciated. Thanks in advance.:realmad:
  2. hydro_37

    hydro_37 PlowSite Veteran
    from iowa
    Messages: 3,790

    There is a heater relay that controls the blower motor speeds. it is located under the hood and just below the fan box. it is a plug in thing. Not sure if that will help it with warmer air or not.
  3. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,525

    Sounds like heater core maybe restricted. Feel both hoses when the motor is hot and heat on. They should be almost the same tempature , If they are not the core is restricted, it can be powerflushed with mixed results, or just replaced. Let us know what u find but that is always a good place to start. I am also assuming ur engine is reaching operating temp and ur t stat is not tuck open? Also sound like mabe ur fan motor is weak. The resistor always works normal on high from what I have seen.
  4. platinumpimps

    platinumpimps Member
    Messages: 43

    thanks for the info. the heater relay sounds like a good place to start. i will be working on the old girl today. crossin my fingers.
  5. Tom McDunnah

    Tom McDunnah Junior Member
    from Maine
    Messages: 19

    It could be the relay in the heater box like was said above.
    It also could be the speed switch control.They do burn up and the wiring also,got to watch out for voltage drops that does alot of damage to light and heater switches,along with the wiring and plug ins

    MAR4CARS Senior Member
    Messages: 246

    Another thing to check is the A/C evaporator if its leaking it will leave an oil residue on the fins which dirt attaches to and will greatly reduce your air flow. First thing to determine is do the other fan speeds work?Normally when you have a bad blower motor resistor you will have only high and none or only a few of the other speeds.
  7. platinumpimps

    platinumpimps Member
    Messages: 43

    it doesnt blow on high, or any other level. im putting in a glow plug controller today, so i can get it started to work on the heat. thanks for all the help!

    MAR4CARS Senior Member
    Messages: 246

    Ok first thing i would do is check for power and ground at blower motor.You can even tap on the blower motor to see if it starts working.Just don't hit it to hard as that is a permanent magnet motor and you will shatter the magnets inside it.
  9. bharry20

    bharry20 Senior Member
    Messages: 124

    if he has to tap on it to get it going I would be looking for a new blower motor. that one is on it's way out.:angel:
  10. MAR4CARS

    MAR4CARS Senior Member
    Messages: 246

    Yeah but if the issue wasn't the blower motor and he hit it hard and busted the magnets now he will need a motor even though it was good to begin with. :)
  11. bharry20

    bharry20 Senior Member
    Messages: 124

    i never said to hit it hard. yes a slight tap will bring a motor, that is just about bad, back to life, and no you should NEVER, EVER, use such force as to bust ANYTHING apart in the motor. i wanted him to be aware of the fact that a slight tap will not fix the problem entirely. :rolleyes:
  12. nyplowguy

    nyplowguy Junior Member
    Messages: 3

    you could also try taking off both heater hoses off the heater core (at the firewall) and spraying some water through there some times if the coolant is old it will coagulate in the core and some pressurized water will push the crap out good luck

  13. cornbinder

    cornbinder Senior Member
    Messages: 348

    my first winter i had a heater core plug up in one of my trucks. i had some liquid acidic stuff i put into the heater core for about 30 seconds and then ricsed it out with water. been blowing hot ever since, 6 years ago. sounds like a combination of things, i have quite a few ford diesels, sometimes in the winter i've had a few that don't warm up very well, once you get the plow on and start working it, chances are unless the heater core is plugged it'll blow warm.check all you connections, grounds you may possibly need a motor. good luck, pete
  14. Brownie

    Brownie Junior Member
    Messages: 1

    I had a 92 f-150 that heater stoped working. If it is blowing cool air, flip your lines going into your heater core. That will reverse the flow in the core. Most times it will work.
  15. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    If you have no blower at all I would bet it's the motor resister. Follow the wires from the motor to it. The thing should be a square thing that is attached to the heater housing. Most times the blower switch in the dash does not go bad often. If you can hear the motor running but no air the control doors may not be working. Some trucks have 2 vacuum actuators that move the doors for A/C and heat. Pull the blower motor and make sure the housing is not full of leaves or a mouse nest.I have seen both on Fords and GM's. If both heater hoses are so hot you can't hold them with your hand you have heat to the core.
  16. platinumpimps

    platinumpimps Member
    Messages: 43

    still waiting on a selonoid for my starter, i put in the new glow plug controller and went to start her up, and all i got was a click. tapped on the starter and i got a little sound from the starter. took the starter out and the selonoid, one of the posts was loose. so i got the wrong one from the parts store, go figure. and waitin on the next one. hopefully they got it right this time or im s.o.l, but then i can get back to the heat problem. ha
  17. Tommy10plows

    Tommy10plows Senior Member
    Messages: 345

    Is this a fan problem for fan flow or is this a temperature problem for heat itself?

    My first step would be to check the coolant level, some trucks do not heat well when the coolant level is below the minimum mark on the fill tank. In the winter I fill mine up to the "hot" mark on the the tank no matter what.

    The next step is to check the flow in the hoses. See if both are warm to the touch. If not your temperature control valve may be stuck. Then go on to the heater core by checking to see if it is clogged on one side or another.

    You might want to check your heater hoses as well. I had a problem once with cheap hoses on the radiator, no wire inside, that would collapse during high RPM's and the engine would starve for coolant and the temperature would rise on my gauge. Inferior or old hoses will do this and starve out the coolant.
  18. platinumpimps

    platinumpimps Member
    Messages: 43

    it is both, no air flow, and no heat coming out
  19. platinumpimps

    platinumpimps Member
    Messages: 43

    Thanks for all your help. I got her blowing hot, all i had to do was tap on the damn fan motor. Now on to my next domino affect inconvienience. I'm going crazy here with this truck. It went from a glow plug controller, to no heat, (reverse that) to a starter, now I'm leaking diesel from up ontop of the motor, on the driver side, from by the glow plugs i think. it is coming out from by there. on two or 3 of the plugs, but im not sure if its coming out below that somewhere or not. im at a complete loss here, and getting very very aggravated. I need to work and need it to pull a damn skid loader tomorrow. Ive been putting off this job because of all these problems, and getting sick to my stomach now. Anyone....>?????